Illuminating instrument dial



Aug. 8, 1939. R. L. TRIPLETT ILLUMINATING INSTRUMENT DIAL Filed March 9, 1937 INVENTOR 1640 L. TE/PLETT ATTQRNEYS.

Patented Aug. 8, 1939 PATENT OFFICE 2,168,720 ILLUMINATIN G INSTRUMENT DIAL Ray L. Triplett, Bluffton, Ohio Application March 9, 1937, Serial No. 129,873

6 Claims.

My invention relates to instrument dials, and in particular, to an attachment for illuminating instrument dials.

It is the object of my invention to provide for the illumination of instrument dials. This is accomplished by the use of a detachable shield used to protect the observer from a direct view of the light source and to make proper distribution of the light over a portion of the dial. While it is my purpose to make the shield detachable which holds the light source, or which may cover the light source only, yet the shield may be built integral within the instrument housin It is my object to provide easy access for renewing the light source and for making zero adjustments to the instrument where such adjustment screw is usually on the-front of the instrument and beneath the shield.

It is an object of my invention to make the shield adaptable to instruments having a standard housing, so that it may be used upon instruments already in use. In order-to eifect the-installation on instruments already in use, the application of the shield only requires the installation of suitable studs through the regular instrument to provide fastenings to secure the shield in place, and to make the electrical connection through these stud fastenings to a source of current for the lamp.

It is a further object in the fasteningof the shield 'to substitute for screws or bolts a compression type clamp and a stud into which the clamp locks to hold the shield securely in place, sothat the shield is quickly detached or quickly mounted and held in place.

It is an object to provide such an arrangement by which the studs serve the dual purpose of holding the instrument on the panel andof locking the shield to the instrument.

Referring to the drawing:

Figure l is a front elevation of the instrument with the lighting shield in place.

Figure 2 is a side elevation of the instrument and the shield showing the supporting surface in section, for supporting the instrument.

Figure 3 is an inside elevation beneath the shield showing the lamp, the method, of holding the lamp, and the compression clamps which conduct the electric current to the lamp terminals.

Figure 4 is a section showing one of the studs for holding the instrument in place to its panel. This stud also serves to hold the shield and is the means for connecting the lamp to the supply source for conducting the electric current to the lamp.

Figure 5 is a top in Figure 3.

Referring to the drawing in detail, I is a portion of the case, preferably of insulating material surrounding the dial 2 of the instrument. The shield 3 is preferably of the same insulating material as the case I. The interior of the shield is preferably painted or formed of lightrefiecting material. The shield is semi-circular or is segmental, that is, less than a full semicircle for a round case, and of corresponding shape for square and rectangular cases.

The shield comprises a marginal rib 4 having slots 5. An enlarged recess portion 6 has a depression l for receiving the lamp 8.

The slots 5 receive the spring fingers 9 which have turned-over ends l0 with a bayonet joint slot comprising an enlarged portion II and a restricted portion l2. The enlarged portion H is adapted to pass over the head l3 of the supporting and conducting stud M, which has a restricted portion l5 that will fit within the restricted portion l2 of the spring fingers 9. The mounting and demounting of the shield 3 will be described hereinafter. This stud I4 is insulated by the sleeve l6 from the case I and the panel support I! for the instrument. The stud l4 also carries the attaching finger l8 to which a conducting wire is soldered. The nut |9 holds the assembly together.

plan view of the shield shown Returning to the shield 3 it will be observed that the finger 9 is supported through an arcuate spring member 29 and an arm 2| upon the inner wall of the rib 4 of the shield 3. It is mounted on this rib by the screw or stud 22, through a U- spring clip finger 23 which extends down into a cut-away portion 24 in the rib 4. The purpose of this spring finger 23 is to form a contact for the end of the lamp 8, as at 25. The lamp is supported within the arcuate spring finger 26 that is mounted by the stud or screw 21 on the inside of the shield 3. This finger 26 is in turn connected to the spring finger 28, 29, and turned-over end 30, which has a similar bayonet slot II and I2 to that formed in the spring finger 9 and its turnedover end l0. This finger 29 likewise extends through a cut-away portion 5 in the rim 4 of the shield 3.

Operation It will be recalled thatthe object of this invention is two-fold: first, to provide a shield for reflecting the light uniformly over the instrument dial without directing the light into the face of the observer; and, second, to provide a 55 ready means of attachment and detachment for the shield, which means will also serve to convey the current to the lamp.

When the shield is pressed with the heads l3 of the studs l4 entering the openings II, the spring fingers will be mounted over the studs 14, and when the pressure is released, the restricted portions I2 will surround the restricted portions l5 of the studs M to hold the shield in place. Likewise, it is desired to detach the shield, by pressing inward on the turned-over ends of the spring fingers 9 and 29, the user can detach the shield by moving the enlarged openings H in alignment with the heads l3 of the studs i4, so that the shield may be slipped off the instrument. When the instrument is so mounted, then the lamp is brought in circuit, so that the studs I4 serve the dual purpose of supporting the shield in place and of acting as conductors for the current to the lamp. The ends l0 and 30 of the spring fingers project from the margin of the shield 3 so that by compressing these fingers, the attachment and detachment may readily take place.

The light from the lamp is reflected against the instrument dial 2 and upwardly over the dial uniformly, because the top of the shield is cut away between ends of the rib i and the front 6 of the shield so that light passes out through the space generally designated 3!.

An additional feature of this shield is that it conceals the zero adjustment screw 32. When it is removed, this screw can be actuated, and when the shield is in place, this screw is hidden, so that it cannot be tampered with.

Other forms of clamping means will be apparent, such as using a single clamp and one or two contacts to guide the shield in place and to make the necesary connections to the lamp terminals. Other guides may be made in the molded portion of the shield or case.

It will be understood that I desire to comprehend within my invention such modifications as may be necessary to adapt it to varying conditions and uses.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In an electrical instrument, an instrument having a dial and a central casing with a laterally projecting rim portion, spaced studs mounted on said laterally projecting portion externally of said instrument casing, a shield having illuminating means mounted on the interior thereof, yielding means on said shield operable from the exterior thereof adapted to be detachably mounted on said studs, and an electrical dial illuminator attached to said shield and electrically connected to said yielding means for receiving electricity therethrough from said studs, said studs being arranged for connection with a source of electrical energy.

2. In an electrical instrument, an instrument having a casing with a dial and a rim flange, spaced studs mounted on the face of said instrument and extending through said rim flange without penetrating said casing, a detachable shield having illuminating means mounted on the interior thereof, yielding means on said shield operable from the exterior thereof adapted to be detachably mounted on said studs, said yielding means having a slot with large and small portions and said studs having heads with large and small portions, whereby when said yielding means are actuated the large slot portions therein will pass over the large head portions of said studs, and when released, the smaller slot portions in said yielding means will engage with the smaller head portions of said studs, to retain the shield in position.

3. In combination, an instrument, a detachably mounted shield thereon, and means for detachably mounting said shield comprising studs on said instrument having an enlarged head and bayonet slots in the ends of yielding fingers on said shield for passing over the heads of said studs and engaging the studs behind said head through said bayonet slots.

4. In combination, an instrument, a detachably mounted shield thereon, and means for detachably mounting said shield comprising studs on said instrument having an enlarged head and bayonet slots in the ends of yielding fingers on said shield for passing over the heads of said studs and engaging the studs behind said head through said bayonet slots, said yielding spring fingers extending beyond the margin of the shield to permit the actuation of the fingers for mounting and demounting the shield.

5. In an electrical instrument, an instrument, a shield, a lamp in said shield, attaching spring fingers mounted on said shield and connected to said lamp, and current-conveying and supporting studs mounted on said instrument adapted to detachably engage with said spring fingers for supporting said shield and conveying current to said lamp, said spring fingers having a bayonet joint slot in the ends thereof and said studs having heads and restricted throats for cooperation with said bayonet slots, whereby the compression of the spring fingers will regulate the attachment and detachment of the shield on the instrument.

6. Anew article of manufacture for use as an illuminating shield for an instrument comprising a shield, a lamp mounted within said shield, said shield being opened at the top and closed at the bottom, spring fingers mounted within said shield yieldingly engaging and supporting said lamp, locking fingers mounted on the ends of said spring fingers and projecting beyond the margins of said shield.

RAY L. TRIPLETT. 

